Why is this game so buggy and unoptimised?

The amount of bugs and the amount of times I’ve seen them repeat is frightening. My framerate also bounces around often, with interesting anomalies such as losing 10 FPS when aiming down sights, and I’m only able to get 50-60 FPS on ultra settings, with it dropping to as low as 30 is some instances despite having a mildly better than average PC.

Steam?
Did you try the beta version which offers some improvements for Performance?

Yeah, Steam. Also, there’s a beta for that? Why isn’t that just in the base game?

For testing purposes.